Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
From a perspective of enhancing a user's convenience, an image forming apparatus, such as a printer, a copier, and a multi-functional peripheral, includes the following functions. That is, the functions include: a function to detect an open/close state of a sheet feed cassette, which houses paper sheets, and a function to detect presence/absence of the paper sheets inside the sheet feed cassette. However, to provide the above-described functions, individually mounting sensors, such as a push switch and a photo interrupter (PI), for each function is required. This causes a problem of cost increase.
In association with recent heated cost competitions, the image forming apparatus omits the sensors. This restricts the above-described functions and supplements the functions by other simple functions. For example, the function to detect the presence/absence of paper sheets inside the sheet feed cassette is replaced by, for example, the following simple function. That is, when a paper feeding operation from the sheet feed cassette is performed first but paper feeding cannot be performed, the function is replaced by a simple function such as displaying a message for a user to replenish paper sheets.
Meanwhile, as a method for ensuring cost reduction while ensuring the above-described functions, for example, the following mechanism has been disclosed. By detecting two states by one sensor, both an open/close state of a sheet feed cassette and presence/absence of paper sheets are detected.